Currently, networks of the second generation global mobile communication technology/third generation global mobile communication technology (2G/3G, 2nd Generation/3rd Generation) have been deployed in many areas.
Based on communication development needs, the third Generation Partnership Project standardization organization introduces a new-generation evolution network, for example, a long term evolution (LTE, Long Term Evolution) network. The new-generation evolution network has covered some urban areas and traffic hot spot areas.
For different network bearer mechanisms, mobile communication services may be divided into:
services borne by a circuit switching (CS, Circuit Switching) domain, for example, voice phone, short message, and supplementary services; and services borne by a packet switching (PS, Packet Switching) domain, including data services, and session services.
Because a 2G network have undergone long term construction, the network coverage of the 2G network is much better than that of a 3G network, and this situation will not change in a short term. Therefore, in order to enable a subscriber to use wireless services in more places, existing 2G/3G terminals usually all support the 2G network. Currently, most of 3G terminals are 2G/3G dual-mode mobile phones (specifically, single-card dual-mode terminals). With the continuous development of the (4th Generation) 4G technology, a terminal that can support LTE will also be gradually popularized in future, and 2G/3G/LTE networks will probably coexist in a long term.
Currently, the 3G network with an advanced standard is suitable for data services, while the 2G network with perfect signal coverage (for example, a global system for mobile communications (GSM, Global System for Mobile Communications)) is suitable for CS domain services (mainly including voice services). When an existing single-card dual-mode terminal performs reselection from one network to another network (for example, performs reselection from a 3G network to a 2G network), a period of time when services are unavailable exists, that is, in this period of time, services are interrupted, and neither CS domain services nor PS domain services can be performed. Moreover, the existing single-card dual-mode terminal has no rapid and effective search solution in network reselection.